class Person(object):
    """人"""
    def __init__(self,name,age):
        self._name=name
        self._age=age

    @property
    def name(self):
        return self._name
    @property
    def age(self):
        return self._age
    @age.setter
    def age(self,age):
        self._age=age

    def play(self):
        print('%s正在愉快地玩耍' % self._name)

    def watch_av(self):
        if self._age>=18:
            print('%s正在观看爱情动作片.' % self._name)
        else:
            print('%s只能看《熊出没》。' % self._name)
class Student(Person):
    """学生"""
    def __init__(self,name,age,grade):
        super().__init__(name,age)
        self._grade=grade
    @property
    def grade(self):
        return self._grade
    @grade.setter
    def grade(self,grade):
        self._grade=grade
    def study(self,course):
        print('%s的%s正在学习%s.'%(self._grade,self._name,course))   

class Teacher(Person):
    """老师"""

    def __init__(self, name, age, title):
        super().__init__(name, age)
        self._title = title

    @property
    def title(self):
        return self._title

    @title.setter
    def title(self, title):
        self._title = title

    def teach(self, course):
        print('%s%s正在讲%s.' % (self._name, self._title, course))

def main():
    stu = Student('王大锤', 15, '初三')
    stu.study('数学')
    stu.watch_av()
    t = Teacher('小鱼干', 38, '砖家')
    t.teach('Python程序设计')
    t.watch_av()


if __name__ == '__main__':
    main()